In a vehicle drive-train such a connecting device serves in particular for engaging an all-wheel shaft or wheel driveshaft, also called an axle driveshaft or side-shaft, or for connecting the two halves of an all-wheel shaft or wheel driveshaft. For example, in a vehicle drive-train having a number of drivable drive axles, it makes it possible to switch over between an all-wheel operating mode, in which more than one or indeed all the drive axles of the vehicle drive-train are driven, and a two-wheel operating mode in which fewer or indeed only one of the drive axles of the vehicle drive-train are driven, and conversely.
For example, DE 198 37 417 A1 (FIG. 2) discloses such a connecting device of a vehicle drive-train for the rotationally fixed connection of two shafts, i.e. an automatic clutch for connecting a front axle to a wheel spindle. The connecting device comprises an electromagnet by which a clutch ring can be moved axially to a first position in which the clutch ring releases an interlock between the shafts, and also comprises a spring by which the clutch ring can be moved axially to a second position in which the clutch ring produces an interlock between the shafts.
The previously unpublished document DE 10 2011 085 839 discloses another connecting device for connecting two shafts. This connecting device comprises on the one hand a sliding sleeve with a groove or step flank arranged on it, and an adjusting means that can be engaged in a switchable manner in the groove/step flank. This displaces the sliding sleeve to a first position when the adjusting means engage in the groove or step flank and the sliding sleeve is rotated, whereby the sliding sleeve releases an interlock between the shafts. On the other hand the connecting device comprises a spring by which, when the adjusting means are disengaged from the groove/step flank, the sliding sleeve can be moved to a second position in which the sliding sleeve produces an interlock between the shafts.
Inasmuch as the shift positions of the clutch ring or the sliding sleeve are defined by a mechanical stop, the impact of the clutch ring or sliding sleeve against the stop can be hard when it is moved to the corresponding shift position. This can lead to disturbing knocking noises.